The invention relates to a method and apparatus for drilling and completing a well and, more particularly, to a method and apparatus for simultaneous drilling and completion which allows for simplified drilling and easier data acquisition and transmission.
In the industry of producing hydrocarbons such as crude oil and gas from subterranean formations, wells are drilled from a surface location to the hydrocarbon bearing formation so as to allow production of the hydrocarbon.
Conventional drilling techniques involve the use of a drilling bit to drill-through various formations utilizing drilling mud which is circulated through a pipe to the drill bit and then back through the well to the surface. The drilling mud helps drill through the desired formation and serves as a vehicle for carrying cuttings from the formation back to the surface.
Drilling mud must be carefully weighted so that the weight of the column of fluid in the well is sufficient to balance formation pressure encountered during drilling. If this is not carefully maintained, high pressure formations can cause various undesirable disruptions in the drilling process. On the other hand, if the drilling fluid is too heavy, drilling fluid can invade and adversely affect potentially hydrocarbon producing formations.
Conventional wells are drilled in sections. After a particular length of a well is drilled, it is conventional to remove the drilling equipment and position a pipe or casing into the well. This casing is then cemented in place, and further drilling can then be carried out through the cemented cased section of the well. Although the casing resolves any potential problems with formation pressure in the drilled section, it should be readily apparent that this reduces the diameter of the originally-drilled hole, and therefore requires that the next section be drilled with a smaller drill bit. The end result is an ever-decreasing size of the well which of course is not desirable. Further, the need for cementing strings of casing into the well delays the drilling procedure and results in an added expense for the cost of pipe and equipment for positioning same.
Horizontal drilling is a development in the drilling art whereby wells are drilled at angles other than substantially vertical so as to reach other desired locations and/or position a well with maximum possible flow area in a producing formation. Unfortunately, horizontal drilling leads to still further complication in connection with positioning and cementing casing into the well.
Another disadvantage of conventional drilling techniques is that the casing, when positioned in the hole, is subject to corrosion, and may be adversely affected by erosion as well. Further, the casing can interfere with communication of electronic devices from the well into the formation, for example during logging and other procedures designed to obtain information about the well and formations which the well has been drilled through.
Based upon the foregoing, it is clear that the need remains for improved processes and devices for drilling and completing wells.
It is therefore the primary object of the present invention to provide such a method and apparatus.
It is a further object of the present invention to provide a method and apparatus which eliminates the need for conventional casing.
It is still another object of the present invention to provide a method and apparatus whereby the well does not have a gradually decreasing diameter.
It is yet another object of the present invention to provide a method and apparatus whereby the well is completed substantially simultaneously with drilling whereby balancing of formation pressure is not necessary.
Other objects and advantages of the present invention will appear hereinbelow.
In accordance with the present invention, the foregoing objects and advantages have been attained.
According to the invention, a method is provided for drilling and completing a well which method comprises the steps of drilling through a subterranean formation with a drill bit so as to form a well bore having a side wall; applying a consolidating material to said side wall under pressure so that said consolidating material flows into said side wall and provides a coated side wall coated with said consolidating material; and passing a scraping member having a desired profile past said coated side wall so as to provide said coated side wall with said desired profile.
In further accordance with the present invention, a drilling assembly for drilling and completing a well has been provided, which assembly comprises a drill bit member having a forward end for drilling through a subterranean formation; a drilling fluid conduit for conveying drilling fluid from surface to said forward end; a recycle conduit for receiving a mixture of said drilling fluid and cuttings from said formation at said drilling end and for conveying said mixture to surface; a consolidating material port positioned behind said forward end for applying consolidating material to walls of a well bore drilled by said forward end; a consolidating material conduit for feeding consolidating material from surface to said consolidating material port; and a consolidating material scraping member having a desired profile and positioned behind said consolidating material port for providing consolidating material on said walls with said desired profile.